JP2002157747A - Optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk that can correctly reproduce data without being affected by layers other than a reproduction layer. SOLUTION: An address area is not vertically arranged in a direction of photo spot traveling so as to decrease a rate of a change in a ratio of a mirror area occupied in the photo spot emitting the other layers resulting in reducing local fluctuations of a reproduction signal of data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk having a plurality of information recording surfaces having the same incident surface for readout light, at least one of which is optically recordable.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for optical discs for video applications, and it is desired to increase the capacity for recording video for a longer time. Hereinafter, a two-layer optical disc will be described as one of approaches to increasing the capacity.

FIG. 10 shows a plan view of a conventional optical disk. The optical disc 1001 is provided with groove-shaped groove tracks 1003 and land tracks 1002 between the grooves. Information is recorded on both tracks,
The peripheral tracks are classified into one or more address areas 1004 and data areas 1005.

Next, reference is made to FIG. FIG. 11 shows the vicinity of the address area 1004 of the optical disc 1001 in more detail. In FIG. 11, for example, address pit groups 1101 and 110 are provided in a groove track 1003a.
2, 1103 and 1104 are provided, and address pit groups 1105 and 110 are provided on the land track 1002a.
6, 1103 and 1104 are provided.

[0005] The data area is usually divided into units called sectors.
One sector is composed of an 8-byte address area, a 2-byte mirror area following the address area, and a 2567-byte data area following the mirror area as minimum units. The data area includes a PLL (Phase Lo).
An actual user data is 2048 bytes (for example, Japanese Patent No. 3025501).

[0006]

However, when a two-layer structure as shown in FIG. 12 is used to further increase the capacity, the following problem occurs. First, in FIG. 12, reference numerals 1201 and 1202 denote transparent substrates such as polycarbonate, 1203 denotes a first recording film, and 1204 denotes 1st recording film.
A semi-transparent reflective film that transmits or reflects a laser beam incident from 201, 1205 is a second recording film, 1206 is 12
1207, a reflection film for reflecting a laser beam incident thereon;
Is an adhesive having a property of transmitting light for bonding the substrate 1201 and the substrate 1202. Here, for example, when reproducing a signal recorded on the second layer of the recording film 1205, a part of the laser light is reflected by the first layer and is collected on the photodetector. Similarly, the first recording film 1
When reproducing the signal recorded in 203, a part of the laser light is transmitted through the first layer, reflected by the second layer, transmitted again through the first layer, and focused on the photodetector. . Thus, when reproducing a signal recorded on the recording film of either the first layer or the second layer, it is affected by stray light of another layer which is not reproduced.

Therefore, in order to obtain a stable reproduction signal,
It is important to reduce the fluctuation of the amount of light reflected from another layer. The amount of light reflected from the other layer greatly varies depending on whether the data area occupies the spot of the laser beam applied to the other layer or the address area.

[0008] As shown in FIG.
In No. 4, compared to the data area 1005, the proportion of the flat mirror area having no grooves and no pits is large, and accordingly, light diffraction is reduced and the amount of reflected light is increased. Therefore, for example, when reproducing the second layer, if the ratio of the address area occupied in the light spot irradiated on the first layer is large,
Unnecessary DC components are superimposed on the reproduced signal amplitude of the layer, and as a result, the reproduced signal fluctuates. This is shown in FIG.

In FIG. 13, reference numeral 1301 denotes recording marks recorded on the second layer, and 1302, 1303, and 1304 denote light spots for reproducing the second layer. 13
Reference numerals 05, 1306, and 1307 denote light spots for irradiating the first layer when reproducing the signal recorded on the second layer. Light spots 1302 and 1305, 1303 and 130
6, 1304 and 1307 correspond in time, and are sets of light spots for irradiating the first and second layers, respectively.

Reference numeral 1309 denotes an envelope of a reproduced signal when the signal recorded on the second layer of the two-layer optical disc is reproduced. Note that reference numeral 1308 denotes an envelope of a reproduced signal when reproducing a signal recorded on a single-layer optical disc having recording performance equivalent to that of the second layer. At 1309, the envelope fluctuates locally compared to 1308.

Since the address area occupies the light spot irradiated by the corresponding first layer light spot 1306 near the position of the light spot 1303, the amount of light reflected from the mirror area is reduced by the second layer. This is because it is superimposed on the reproduction signal.

When such unnecessary DC components are superimposed, local variations occur in the reproduced signal, and the sections 1310 and 1311
In such a place where the envelope fluctuation is large, the reproduced signal cannot be properly binarized. Conversely, if the operating frequency of the binarization circuit for obtaining the binarized signal is increased to follow the rapid fluctuation of the envelope, the signal follows the signal which should not be followed, such as a defect. As a result, the reproduction performance decreases.

As described above, the conventional address allocation method is
When used for a layer disc, there is a problem that a reproduced signal is erroneously binarized at a place where the envelope fluctuates greatly and correct data cannot be reproduced.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an optical disk capable of correctly reproducing data without being affected by layers other than the reproducing layer.

Further, in the conventional format, as described above, when recording 2048 bytes of user data on a disk, a total sector length of 2697 bytes was required. That is, the format efficiency is 2048/2.
697 = 0.759, and the disk use efficiency (format efficiency) when recording a signal on the disk is 75.
9%, and 24.1% was a format including redundancy.

For example, when recording a capacity of 4.7 GB,
Format efficiency of 100% and 75.
With the format efficiency of 9%, in the latter case where the format efficiency is low, more information must be packed per unit area, and therefore, there is a problem that the quality of the recording / reproducing signal is deteriorated as compared with the former.

In view of the above problems, the present invention further reduces the redundancy used in the address area by creating an address format with high format efficiency, and records more data on an optical disk of the same size. It is an object of the present invention to provide an optical disk capable of performing the operation.

[0018]

In order to solve this problem, an optical disk according to the present invention has at least a first layer and a second layer information recording surface, and at least the first layer of the information recording surface is optically movable. In an optical disc which is an information recording surface recordable on a data layer, the information recording surface of the first layer has a data area and an address area for specifying the location of the data area, and the address area is formed of uneven pre-pits, The address area is arranged so as to be shifted by a substantially constant disk center angle θ (angle at the center of the disk) every time the address area is shifted by a certain amount in the radial direction of the disk, and the address information of the address area is 1 bit. The first code "0" to represent
, The second code “1”, and the third identification code “S”.

In order to solve this problem, in the optical disk of the present invention, the address area is composed of at least one or two pre-pits, and the first pre-pit and the second pre-pit following the first pre-pit with a space interposed therebetween. The length P1 of the first prepit is compared with the length P2 of the second prepit. If P1> P2, the first code is “0”, and if P1 <P2, the first code is “0”. The second code is “1”, and the case of P2 = 0 is a third identification code “S”.

According to another aspect of the present invention, there is provided an optical disc having a concentric or continuous spiral groove and an inter-groove portion on an information recording surface, wherein an address area includes the groove portion and a track center of the inter-groove portion. They are arranged in a zigzag pattern at a predetermined distance from the line to the inner peripheral side and the outer peripheral side, respectively.

According to another aspect of the present invention, there is provided an optical disk according to the present invention, wherein an area sandwiched between two address areas in a track direction is defined as one sector, and a block address is provided for each block including a plurality of continuous sectors. Information, and the block address information is configured by combining address information of two or more address areas.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical disc according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of an optical disk according to the present invention. In FIG. 1, reference numerals 101 and 102 denote transparent substrates made of polycarbonate or the like; 103, a first recording film;
04 is a translucent reflective film that transmits or reflects the laser light incident from 101, 105 is the second recording film, and 106 is 1
Reference numeral 107 denotes a reflection film that reflects the laser light that enters from 01, and an adhesive having a property of transmitting light for bonding the substrate 101 and the substrate 102 together.

Referring now to FIG. FIG. 2 is a plan view of the optical disk shown in FIG. In FIG. 2, 201, 20
5 is an address area, and 202 and 206 are data areas. 203 and 207 are groove-shaped groove tracks, 2
04 and 208 are land tracks between the grooves. The groove-shaped groove tracks and the land tracks between the grooves are provided concentrically or spirally.

Information is recorded on both tracks, and the tracks are divided into an address area and a data area. The track may be a disk in which a land track and a groove track are connected in a continuous spiral for each round.

As shown in FIG. 2, the address areas are arranged so as to be shifted by a substantially constant disk center angle θ (angle at the center of the disk) for each track, and are arranged in a spiral. In the present embodiment, the arrangement of the address areas is not aligned in the radial direction when tens of tracks are observed. That is, the tangent direction of the arrangement of the address areas does not coincide with the radial direction.

The arrangement of the address area is not limited to FIG.
For example, as shown in FIG. 3, the zone may be radially divided into several zones (for example, an inner zone, a center zone, and an outer zone). The optical disk shown in FIG. 3 may have a constant angular velocity format or a constant linear velocity format. In FIG. 3, the interval between adjacent address areas in the track direction is particularly constant. A group of the address areas in which the address areas are arranged so as to be inclined with respect to the radial direction is referred to as an inclined address area group. FIG. 4 shows an enlarged view of the address area in FIG.

In FIG. 4, reference numeral 401 denotes a groove track,
402 is a land track, 403, 404, 405, 4
Reference numeral 06 denotes a pit string forming an address area. 403
The set of 404 and the set of 405 and the set of 405 and 406 are arranged in a zigzag manner at a predetermined distance from the center line of the track to the inner circumference and the outer circumference, respectively. In addition, for example,
The staggered pit row is arranged as shown in FIG. 4 so that the inner pit row viewed from the groove track and the outer pit row of the inner groove track are not adjacent to each other, as shown in FIG. It is desirable that the rows (403, 404) be arranged in a direction approaching the boundary position of the adjacent groove track.

Next, reference is made to FIGS. FIGS. 5 and 6 show the state of the light spot 501 applied to the first layer when reproducing the second layer. FIG. 5 (a)
3 corresponds to the optical disk shown in FIG.
FIG. 5 shows a state in which the address areas are completely included. FIG. 5B, which is a conventional configuration for reference, shows a vertical address area group 503 having no inclination (the address areas arranged in the radial direction). (Gathering) is completely included in the light spot 501.

FIG. 6A corresponds to the optical disk shown in FIG. 2 and shows a state in which the inclined address area group 505 crosses the light spot 501 diagonally. FIG. 6B shows a state in which the vertical address area group 506 crosses the light spot 501 vertically.

Since the address area occupies the light spot 501, the amount of light reflected from the mirror portion of the address area is superimposed on the reproduction signal of the second layer, and the reproduction apparatus has a local change in the reproduction signal amplitude due to the superposition. If the slice level cannot be followed, correct reproduction cannot be performed.

Here, the inclined address area group 5 shown in FIG.
02 and the conventional vertical address area group 503 in FIG. It is assumed that the width W of the inclined address area group 502 and the width W of the vertical address area group 503 are equal. In the state where the address area group is completely included in the light spot as in the illustrated state, the ratio of the area occupied by the address area group in the light spot is different from the case of FIG. (B)
Is almost equal to However, when the light spot 501 shifts in the track direction, that is, in the left or right direction due to the lapse of the time Δt, for example, when the light spot 501 shifts to the position of the light spot 501-a shown in FIGS. 5A and 5B, A part Δs of the inclined address area group 502 is a light spot 501-a.
On the other hand, since the vertical address area group 503 is still completely contained in the light spot 501-a, the ratio of the area occupied by the light spot 501-a is as follows.
Slant address area group 5 than vertical address area group 503
02 is smaller.

When the time Δt further elapses and the light spot shifts to the position of the light spot 501-b, a part (about 2 Δs) of the inclined address area group 502 becomes light spot 501.
While, about half of the vertical address area group 503 (about 2Δs) is shifted out of the light spot 501-b.

The change amount Δs of the area occupied by the address area in the light spot 501 with respect to the time change Δt is represented by
In this case, the degree of change F is expressed by the following equation.

F = Δs / Δt According to the above example, in the case of the inclined address area group 502, the increase / decrease Fs is Δs / Δt, whereas in the case of the vertical address area group 503, the increase / decrease Fv Is 2Δs / Δ
t, and the degree of change is about twice. The increase / decrease Fs in the case of the inclined address area group 502 changes depending on the inclination angle and the width W of the area group, but is always smaller than the increase / decrease Fv in the case of the vertical address area group 503. Since the inclination is preferably smaller, the inclination address area group 502 is more preferable than the vertical address area group 503.

Therefore, by arranging the address area extending in the radial direction obliquely with respect to the light spot traveling direction, it is possible to improve the reproduction performance as compared with the case where the address area is arranged perpendicularly.

Next, referring to FIGS. 6A and 6B, the inclined address area group 505 and the conventional vertical address area group 50 will be described.
Compare 6. The apparent width We measured in the tilt direction is smaller than the width W of the tilt address area group 505. Therefore, in addition to the same effect as in the case of FIG. 5, the apparent width We of the inclined address group 505 is smaller than the width W of the vertical address group 506.
The change Fs in the case of 5 is smaller than the change Fv in the case of the vertical address area group 506. Therefore, in FIGS. 6 (a) and 6 (b) as well, by arranging the radially extending address area obliquely with respect to the light spot traveling direction, it is possible to enhance the reproduction performance as compared with the case where the address area is vertically arranged. Can be.

The same applies to the arrangement of the address areas of the second layer when reproducing the first layer. By arranging the address areas in the radial direction obliquely with respect to the light spot traveling direction, Reproduction performance can be improved as compared with the case of vertically disposing.

As described above, in the layer other than the reproduction layer, by not arranging the address area perpendicular to the traveling direction of the light spot, data can be correctly reproduced without being affected by the layers other than the reproduction layer. .

Although the track is not wobbled in FIGS. 4, 5 and 6, the same effect can be obtained even if the track is wobbled.

Next, reference is made to FIG. FIG. 7 is a track configuration diagram for explaining an address format. FIG.
701 is a groove track and 702 is a land track. Address area 703 and data area 7
04 forms one sector 705. Further, a plurality of sectors are gathered to form a block 708.

As shown in FIG. 7, the address area is located at the beginning of the groove sector or land sector, and is shifted from the groove track center line or land track center line by half a track toward the inner circumference and the outer circumference, respectively. Are located. In addition, in the address area of each sector, especially the address area ahead is set as ID1,
The rear address area is ID2.

Further, a part of the address information of the land sector or the groove sector is assigned to ID1 or ID2. For example, a part of the address information of the groove
D1, a part of the address information of the land sector is assigned to ID2. A part of the address information of the groove sector may be assigned to ID2, and a part of the address information of the land sector may be assigned to ID1.

Further, the address information of the block is constituted by reading the ID of a plurality of continuous sectors. In the case of FIG. 7, the address information includes four consecutive sectors (sector # 0, sector # 1, sector # 2, and sector # 3).
Is read to obtain one piece of address information.

Next, the structure of the address information will be described with reference to FIG. “S” (identification code) is assigned as address information to ID2 at the head of sector # 0 of the land track. By reading the identification code “S”, it is identified that the block is the start position (start sector position). Next, a code “1” is assigned as information of ID2 at the head of sector # 1. Similarly sector #
2. Read the address information of ID2 at the head of sector # 3.

In the case of FIG. 7, a block is composed of four sectors, and "S", "1" and "0" are sequentially provided from sector # 0.
The address information of the block is "S100". Here, the identification code “S” indicates the start position of the address information, and three codes “1” or “0” following the identification code “S” become binary information, which is the address information. For example, in the case of “S100”, if it is changed to decimal notation, it becomes “4”, and it can be identified that the block is the fourth address.

Next, the physical structure of the ID will be described with reference to FIG. In the ID, a part of information (so-called address information) for specifying the position of the data area includes a first code “0”, a second code “1”, and a third identification code “S” representing one bit. "Are provided with any of the three types of codes.
First, in FIG. 9, reference numeral 901 denotes a light spot, which is scanned from left to right in the figure. Reference numeral 902 denotes an ID portion pattern formed on the disk representing the code “0”, reference numeral 903 denotes an ID portion pattern formed on the disk representing the code “1”, and reference numeral 904 denotes a pattern on the disk representing the code “S”. 5 shows a pattern of an ID portion formed in the image data.

The pattern 902 with a code "0" is composed of two pits P1, P2 and a space S1 sandwiched between P1, P2. The pit length of P1 is a mark length corresponding to eight times the length of Tw when the channel clock is Tw, P2 is a mark length corresponding to four times the length of Tw, and S
1 is a space length corresponding to four times the length of Tw. Here, the magnitude relationship between the lengths of P1 and P2 is P1> P2
It has become. S1 = P2.

The pattern of reference numeral “1” 903 is composed of two pits P1, P2 and a space S1 sandwiched between P1, P2. The pit length of P1 is a mark length equivalent to four times the length of Tw, assuming that the channel clock is Tw, P2 is a mark length equivalent to eight times the length of Tw, S
1 is a space length corresponding to four times the length of Tw. Here, the magnitude relationship between the lengths of P1 and P2 is P1 <P2
It has become. S1 = P1.

The pattern "S" at 904 is composed of one pit P1. The pit length of P1 is a mark length corresponding to 16 times the length of Tw, assuming that the channel clock is Tw. S1 = P1.

Symbol “0”, symbol “1”, symbol “S” is P
1, P2 is assigned as follows according to the magnitude relation.

(1) P1> P2: Code “0”.

(2) P1 <P2: Code “1”.

(3) Only P1 (P2 = 0): Code "S".

Here, the pit length of P1 and P2 is 4T.
Although the lengths of w, 8Tw, and 16Tw are used, the pit length does not need to be limited to the numerical values, and can be determined according to the size of the light spot irradiated on the disk. In the reproduced signal, the difference in the pit length between P1 and P2 is determined from the reproduced waveform to identify the code.

According to this embodiment, for example, 12
It is possible to shorten the header part using 8 bytes to 4 bytes, and as a result, it is possible to further reduce the influence of layers other than the reproduction layer. In addition, a format with reduced redundancy becomes possible, and the recording capacity of the optical disc is reduced.
In addition to the effect of two layers, it can be further increased.

[0057]

As described above, according to the optical disk of the present invention, the address area in which about 1 bit of information is formed is not arranged perpendicularly to the light spot traveling direction, so that the layers other than the reproducing layer can be formed. Data can be correctly reproduced without being affected by the above. In addition, a format with reduced redundancy becomes possible, and as a result, the recording capacity of the optical disk can be dramatically increased.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical disc according to an embodiment of the present invention.

FIG. 2 is a plan view of the optical disc in the embodiment of the present invention.

FIG. 3 is a plan view of the optical disc in the embodiment of the present invention.

FIG. 4 is an enlarged view of an address area according to the embodiment of the present invention.

FIG. 5 is an enlarged view of an address area in the embodiment of the present invention.

FIG. 6 is an enlarged view of an address area according to the embodiment of the present invention.

FIG. 7 is a configuration diagram of a track according to the embodiment of the present invention.

FIG. 8 is a configuration diagram of address information according to the embodiment of the present invention.

FIG. 9 is an explanatory diagram of a physical configuration of address information according to the embodiment of the present invention.

FIG. 10 is a plan view of a conventional optical disc.

FIG. 11 is an enlarged view of an address area in a conventional example.

FIG. 12 is a sectional view of an optical disk in a conventional example.

FIG. 13 is an explanatory diagram of a reproduced signal in a conventional example.

[Explanation of symbols]

 101 first layer substrate 102 second layer substrate 201 address area 202 data area 502 inclined address area group 503 vertical address area group 505 inclined address area group 506 vertical address area group 703 address area 704 data area 705 sector 708 block

Continuing on the front page (72) Inventor Atsushi Nakamura 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Inventor Shigeru Furumiya 1006 Kadoma Kadoma, Kazuma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 1-280 Higashi Koigakubo, Tokyo Kokubunji-shi F-term (reference) 5D029 JB13 WA20 WA28 WC09 WD11 5D044 BC06 CC06 DE03 DE33 DE76 5D090 AA01 BB04 BB12 CC14 DD01 FF04 GG09 GG16 GG23

Claims (4)

[Claims] 1. An optical disc having at least a first layer and a second layer information recording surface, wherein at least the first layer of the information recording surface is an optically recordable information recording surface. The information recording surface has a data area and an address area for specifying the location of the data area. The address area is composed of uneven pre-pits, and the address area is substantially deviated by a certain amount in the radial direction of the disk. The address information of the address area is arranged so as to be shifted by a fixed disk center angle θ (the angle at the center of the disk), and a part of the information for specifying the position of the data area is:
A first code “0” representing one bit and a second code “1”
And an optical disc provided with one of three kinds of codes, namely, a third identification code "S". 2. An address area comprising at least one or two address areas.
The first pre-pit is composed of two pre-pits, the first pre-pit, and the second pre-pit that continues across the space from the first pre-pit. In comparison, a case where P1> P2 is set to a first code “0”, a case where P1 <P2 is set to a second code “1”, and a case where P2 = 0 is set to a third identification code “S”. The optical disk according to claim 1, wherein: 3. The information recording surface has concentric or continuous spiral grooves and inter-grooves, and the address area is defined on the inner peripheral side and the outer peripheral side from the track center line of the grooves and the inter-grooves, respectively. 3. The optical disk according to claim 1, wherein the optical disks are arranged in a staggered manner at a distance of. 4. A data area sandwiched between two address areas in a track direction is defined as one sector, and block address information is given to each block composed of a plurality of consecutive sectors. 4. The method according to claim 1, wherein the address information is configured by combining two or more pieces of address information of the address area.
An optical disc according to any one of the preceding claims.